Kinetic energy absorbing element

Abstract

The deformable element for absorbing kinetic energy is a plastic pipe section ( 1 ) having interior surfaces at opposite ends thereof. The plastic pipe section ( 1 ) initially deforms elastically under an applied axial force (F) and, when a yield stress limit is exceeded by the applied axial force (F), the plastic pipe section ( 1 ) deforms or collapses with an approximately equal deforming force over a work stroke until adopting a physically deformed shape in which the interior surfaces at the opposite ends contact each other. The device for absorbing kinetic energy is also described including several plastic pipe sections stacked in a column with an intermediate plate between each adjacent pair of pipe sections. The plastic pipe sections and engaged around a tubular round body for support and guidance. An inner screw bolt can also be provided for pre-tensioning the plastic pipe sections.

What is claimed is:  
     
       1. A device for absorbing kinetic energy operating mechanically according to the principle of plastic deformation, said device consisting of 
       a plurality of plastic pipe sections ( 1 ) arranged in a column;  
       a round body ( 3 ) engaged in the column for holding and guiding said plastic pipe sections ( 1 ); and  
       an intermediate plate ( 2 ) arranged between each adjacent pair of said plastic pipe sections;  
       wherein each of said plastic pipe sections ( 1 ) has interior surfaces at opposite ends thereof and initially deforms elastically under an applied axial force (F) and, when a yield stress limit of each of said plastic pipe sections ( 1 ) is exceeded by said applied axial force (F), each of said plastic pipe sections ( 1 ) deforms or collapses with an approximately equal deforming force over a work stroke until adopting a physically deformed shape in which said interior surfaces at said opposite ends contact each other.  
     
     
       2. A device for absorbing kinetic energy operating mechanically according to the principle of plastic deformation, said device consisting of 
       a plurality of plastic pipe sections ( 1 ) arranged in a column;  
       a round body ( 3 ) engaged in the column for holding and guiding said plastic pipe sections ( 1 );  
       an inner screw bolt ( 4 ) for pre-tensioning the plastic pipe sections ( 1 ); and  
       an intermediate plate ( 2 ) arranged between each adjacent pair of said plastic pipe sections;  
       wherein each of said plastic pipe sections ( 1 ) has interior surfaces at opposite ends thereof and initially deforms elastically under an applied axial force (F) and, when a yield stress limit of each of said plastic pipe sections ( 1 ) is exceeded by said applied axial force (F), each of said plastic pipe sections ( 1 ) deforms or collapses with an approximately equal deforming force over a work stroke until adopting a physically deformed shape in which said interior surfaces at said opposite ends contact each other.